Subject: Re: [PATCH net-next] mlxsw: spectrum_router: Do not allow ipv6 gateway with v4 route via replace

From: Ido Schimmel <[email-masked]>
Date: Tue, 23 Apr 2019 05:36:02 +0000

On Mon, Apr 22, 2019 at 03:42:14PM -0700, David Ahern wrote:
> From: David Ahern <[email-masked]>
> 
> mlxsw currently does not support v6 gateways with v4 routes. Commit
> 19a9d136f198 ("ipv4: Flag fib_info with a fib_nh using IPv6 gateway")
> prevents a route from being added, but nothing stops the replace. Add
> a catch for it too.
>     $ ip  ro add 172.16.2.0/24 via 10.99.1.2
>     $ ip  ro replace 172.16.2.0/24 via inet6 fe80::202:ff:fe00:b dev swp1s0
>     Error: mlxsw_spectrum: IPv6 gateway with IPv4 route is not supported.
> 
> Signed-off-by: David Ahern <[email-masked]>
> ---
>  drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> index 34d9053e5cf0..d21b73236971 100644
> --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> @@ -6109,6 +6109,8 @@ static int mlxsw_sp_router_fib_event(struct notifier_block *nb,
>  			NL_SET_ERR_MSG_MOD(info->extack, "FIB offload was aborted. Not configuring route");
>  			return notifier_from_errno(-EINVAL);
>  		}
> +		/* fall through */
> +	case FIB_EVENT_ENTRY_REPLACE:

Good catch!

I think we need to have FIB_EVENT_ENTRY_REPLACE and
FIB_EVENT_ENTRY_APPEND right after FIB_EVENT_ENTRY_ADD. We want to
prevent route replace and append in case of abort and also prevent
replace/append of IPv4 routes with IPv6 nexthop.

>  		if (info->family == AF_INET) {
>  			struct fib_entry_notifier_info *fen_info = ptr;
>  
> -- 
> 2.11.0
>